1. Field of the Invention
This invention relates to a solar cover for a motor vehicle roof with an outside pane, an inside cover and a plurality of solar cells which are located between the outside pane and the inside cover, both the outside pane and also the inside cover being made of plastic.
2. Description of Related Art
One such solar cover is known from DE 198 13 324 corresponds to U.S. Pat. No. 6,155,635 which describes a solar cover in which, between an essentially flat outside cover plate and an essentially flat inside cover, there is a plurality of solar cells. The cover plate is preferably a glass plate, but can also be a plastic plate made, for example, of plexiglass (PMMA). The inside cover is preferably formed from a plastic film, but can also be made of metal or glass. Published German Patent Application No. DE 198 13 324 A1 corresponds to U.S. Pat. No. 6,155,635 and discloses two embodiments of the solar cover, a frameless one and alternatively one with an additional peripheral solid plastic profile frame. In the frameless embodiment the stability of the solar cover is determined mainly by the cover plate which must be made correspondingly thick, and thus, heavy in order to impart to the cover sufficient stability. The alternative embodiment in production requires the additional working step of peripherally foaming the cover to the plastic frame.
Furthermore, published German Patent Application DE 197 16 389 A1 discloses a solar cover for a motor vehicle roof in which, between an inside plastic support and an outside glass cover layer, there is a plurality of solar cells which are embedded in an adhesive layer. To reduce the weight of the solar cover, the glass cover layer is made extremely thin so that it performs essentially only the function of a scratch-resistant protective cover for the solar cells. According to published German Patent Application DE 197 16 389 A1, a relatively lightweight cover can be produced, but the risk of damage to the cover is relatively high because the thin glass cover layer is not sufficiently supported by the underlying flexible adhesive layer when pressure is exerted from above on the solar cover, for example if a falling article should hit the cover or someone supported himself on the cover.
A primary object of this invention is to devise a solar cover of the initially mentioned type, which is light and still stable and which can be produced in a few working steps.
In a solar cover for a motor vehicle roof with an outside pane, an inside cover and a plurality of solar cells located between the outside pane and the inside cover, both the outer pane and also the inside cover being made of plastic, this object is achieved in accordance with the invention in that the outside pane or the inside cover is formed by an injection molded part which has reinforcement and/or attachment elements which are made in one piece. Because, on the one hand, both the outside pane and also the inside cover as such are made of plastic, and on the other hand, the reinforcement or attachment elements, which in existing roofs were separate components conventionally made of metal, are produced in one working step in the injection molding of the outside pane or the inside cover, the weight of the solar cover made in accordance with the invention can be kept low and the resources which are otherwise required for installing the reinforcement or attachment elements, such as the material cost, tool cost and labor input, are saved.
Since, for reasons of stability and safety, the outside pane should be made clearly more stable than the inside cover which can be a film or a plate, with a thickness which is much less than that of the outside pane, the arrangement is preferably chosen such that the injection molded part forms the outside pane of the solar cover. In this way, an especially lightweight and still stable cover can be produced.
Furthermore, the weight of the solar cover made according to the invention can be kept low by the reinforcing elements which are made in one piece comprising a hollow section which can be for example a U section which runs along the side edge of the cover or a closed hollow section.
In another embodiment of the invention, the attachment elements, which are made in one piece, comprise means for attaching a seal, attachment elements for connection to the fixed motor vehicle roof, attachment elements for connection to a roof mechanism for moving the cover element, and the like. These components can be made in one working process in one piece with the injection molded part which forms the outside pane or the inside cover or can be molded in one piece onto the already pre-cast injection molded part.
Conventionally the solar cells can be embedded in a hot melt adhesive film, for example, ethylene vinyl acetate, or in a sealing compound, for which for example addition cross-linked bi-component silicone rubber can be used.
In the edge area of the outside pane there can be an opaque material, especially to prevent viewing of the reinforcement and/or attachment elements made in one piece from the outside or to cover printed conductors as are provided for making contact with the solar cells and for connecting the solar cell assembly to the vehicle electrical system of the motor vehicle.
The opaque material can be a colored layer or a region of opaque material which is injected onto the outside pane in another working process.
In order to protect the top of the outside pane against damage, especially against UV effects or scratching, it can be coated with a transparent protective varnish. Polysiloxane varnishes,xe2x80x9corcomersxe2x80x9d or nanometer layers can be used as especially advantageous coatings.